It is known to pack particles in a container. For example, it is known to ship plastic resin particles in a large bulk box-shaped container or toner carrier particles in 55-gallon cylindrical-shaped drum container.
It is also known to use a vacuum feed nozzle to remove such particles from the container. For example, at the internet web address xe2x80x9cwww.piab.comxe2x80x9d there is provided information of various xe2x80x9cvacuum conveyorxe2x80x9d products available from the Swedish supplier PIAB AB, whose mailing address is P.O. Box 4501, SE-183 04 Txc3xa4by, Sweden.
However, there are problems with this vacuum-feed-nozzle process of removing particles from cylindrical-shaped containers or box-shaped containers. For example, assume that containers are initially only 50% filled with about 700 pounds of plastic resin or toner carrier. When the level in the drum gets down to the last 3 or 4 inches, with 150 pounds of plastic resin particles or toner carrier particles still remaining in the container, the nozzle will clear a hole around itself and no longer pick up material. To get the last 25% of plastic resin or toner carrier particles out of the container an operator must manually manipulate the nozzle every couple minutes until the level is low or light enough that the container liner bag can be picked up and dumped into another open container. The extra manpower required for attending the nozzle is a problem and frequent cause of downtime. Also as operators are attending the feed nozzle and dumping bags, there might be a safety hazard presented to the human operators, as the humans might be exposed to health hazards such as, for example, inhaling harmful material or fumes related to the plastic resin or toner carrier. For example, recently a human operator was diagnosed with a lung inflammation condition named xe2x80x9cinterstitial pneumonitusxe2x80x9d caused by toner carrier particles entering his lungs.
There are several existing methods to solve the problem of having to attend to the feed nozzle but these methods are more costly, complex, require more floor space, and create other safety hazards. A method, as used in several plants, is conveying out of a fixed carrier supply hopper that holds 3-5 containers of carrier. The hoppers used are loaded by a dedicated container dumper. Special perimeter guarding and safety mats are required around the container dumper because when the drum is lifted into the air serious hazards exist under and near it. In another plant a fork truck using a special container handling attachment dumps the carrier into a supply hopper. There are dedicated hoppers and container dumpers for each pack line and sometimes for each carrier type, thus requiring a large amount of floor space. An other existing method is to place the drum onto a container tilter. The carrier flows toward the corner of the tilted container where the nozzle is located allowing almost all the carrier to be sucked out without manipulation of the nozzle. This method works well but the container tilter device takes up a minimum of 20 square feet of floor space. Also, when the container is tipped there is a hazardous area underneath that must be guarded in some way, thus taking more floor space. Another drawback to using the tilter is the container must be handled requiring a fork truck with a special attachment to lift the container off the skid and place it on the drum tilter.
Moreover, this problem is currently addressed by adding capital equipment such as container tilters, fork truck container handling tools, container dumpers, and supply hoppers. This equipment adds complexity and cost, increases material handling of the drums and plastic resin particles or toner carrier particles, creates new safety hazards and spill risks, and requires a much larger floor space.
In one aspect of the invention, there is described a container having a container inner wall, a container inner bottom with a ramp disposed thereon, the ramp having an included ramp base that is narrower than the container inner bottom, the ramp forming a conical-shaped inclined ramp surface that extends upwardly from the ramp base at a substantially constant ramp surface angle with respect to horizontal towards the container inner wall, the inclined ramp surface defining a ramp upper rim that is substantially proximate to the container inner wall. In one embodiment, the container is cylindrical-shaped. In another embodiment, the container is box-shaped.
In another aspect of the invention, there is described a method of removing particles that are disposed in a container having a container inner wall, a container inner bottom with a ramp disposed thereon, the ramp having an included ramp base that is narrower than the container inner bottom, the ramp forming a conical-shaped inclined ramp surface that extends upwardly from the ramp base at a substantially constant ramp surface angle with respect to horizontal towards the container inner wall, the inclined ramp surface defining a ramp upper rim that is substantially proximate to the container inner wall, the particles having an angle of repose that is less than the ramp surface angle and flow down the inclined ramp surface towards the ramp base, the method comprising removing particles using a vacuum feed nozzle that is disposed proximate to the particles in the container. In one embodiment, the container is cylindrical-shaped. In another embodiment, the container is box-shaped.